In the related art, a shredder is used in erasing an image containing confidential information or personal information (hereinafter, referred to as “confidential information or the like”) which is printed on a sheet. However, in the case of the shredder, a load of a user increases as the amount of sheets which are to be shredded increases.
In addition, when the user stamps an image having a special printing surface pattern on the confidential information or the like, visibility of the image containing the confidential information or the like also easily deteriorates.
However, in this case, the load of the user increases as the amount of the sheets which are the targets to be erased increases, similarly to in the case of the shredder. Such a problem is not limited to erasing the image of the confidential information or the like printed on the sheet, but is common to all of the cases where the user desires to erase the printed image on the sheet.